| 摘要: |
| 提出了一种基于自由形变（free-form deformation，简称FFD）及外轴投影（external axes projection，简称EAP）的复杂表面重构算法.该算法以目标形状的切片轮廓作为输入数据，此后，轮廓被嵌入到高维空间有向距离场中，在此隐式空间中，算法主要分为以下3步：生成计算序列，计算序列由计算单元组成，每一个计算单元包含上下相邻的两个轮廓；根据相邻轮廓间的拓扑关系，进行外轴投影（EAP），以解决潜在的分支问题；在每个计算单元中，根据轮廓长度决定自由形变方向，并进行自由形变，根据自由形变结果，建立轮廓间顶点的一一对应关系，并以此进行表面重构.该方法具有以下特点：输入轮廓可具有任意拓扑结构；所生成表面与输入轮廓完全贴合，生成表面准确，无自我重叠，拓扑关系不发生改变；算法高度并行，执行效率高.实验结果表明，该算法可以解决复杂表面的重构问题. |
| 关键词: 表面重构 自由形变 外轴投影 分支问题 对应关系 |
| DOI：10.13328/j.cnki.jos.005079 |
| 分类号: |
| 基金项目:国家自然科学基金（61300074，61272357，61370131）；教育部新世纪优秀人才支持计划（NCET-10-0221） |
|
| Surface Reconstruction of Complex Shapes Based on Contour Deformation |
|
ZHANG Ya-Lan, BAN Xiao-Juan, LIU Xu, LIU Xi
|
|
School of Computer & Communication Engineering, University of Science & Technology Beijing, Beijing 100083, China
|
| Abstract: |
| In this paper, a novel reconstruction method based on free-form deformation (FFD) and External Axes Projection (EAP) is presented to improve the surface smoothness effect of 3D reconstruction. The contours of the slices are implicitly embedded in a higher dimensional space of distance transforms. In this implicit embedding space, reconstruction is formulated as follows. First, an arrangement of the planar slices is computed to support the approach. The arrangement consists of cells, and each cell consists of two adjacent contours. Second, the branching problem is converted into one-to-one case by the external axes projection. Next, computing direction for each cell of the arrangement is decided by the length energy. Then, in each cell a B-spline based free-form deformation is used to establish the correspondence between the adjacent contours. Finally, the contours are stitched together based on the correspondence. The key advantage of such framework are:(1) it naturally deals with contours of arbitrary topology, and it preserves shape topology; (2) the established one-to-one correspondences between two adjacent contours can guarantee the surface is continuous and no intersection; and (3) this framework is highly parallel. Experimental results show that the proposed approach performs well and can handle complicated situations. |
| Key words: reconstruction free-form deformation external axes projection branching problem correspondence |
